Preselector for radio-frequency network



May 3, 1949. J. H. WILLIAMS 2,469,189

PRESEILEC'IOR FOR RADIO FREQUENCY NETWORK Filed May 5, '194e MECHAN/SM 56 @mima Patented May 3, 1949 UNITED PRESELECTR FR RADIO-FREQUENCY NETWORK .lohn H. Williams, Chicago, Ill., assigner to Oak Mfg. Co., Chicago, Ill., a corporation of Illinois Application May 3, 1946, Serial No. 666,970

(Cl. Z50-40) 2 Claims.

This invention relates to an electrical apparatus and particularly to a preseiector mechanism. Preselecting mechanisms are in wide use in radio receivers and similar apparatus. rhe invention hereinafter described relates particularly to a preselecting mechanism for use in a radio receiver or transmitter adapted to operate selectively in one of two wave bands, the choice being determined by the operator. For convenience, the invention will be described in connection with a radio receiver operating in the standard broadcast band and in the frequency modulation band. In accordance with well known. usage, the broadcast band will be designated as amplitude modulated, while the frequency modulated band will be designated as frequency modulated. It is understood, however, that any two wave bands may be utilized.

Radio receivers in general may have one or more tunable elements or selecting a desired frequency in a particular wave band. As a rule, the wave band itself is selected by suitable switching mechanism. All tunable ele-ments are generally operated by the manual selecting means for controlling station selection, and the particular wave band switched in determines the active set of tunable elements.

For convenience, the tunable elements will be considered as gang condensers although other tunable means such as permeability type tuners are considered to be within the scope of this invention.

The invention in general provides simple means cooperating with every push rod of a preselector, which means selects one oi two wave bands from which the particular station selection is to be made. Thus, if AM and FM bands are to be received, any one or more of the push buttons will not only serve to pretune the receiver but will also select which band is to be received.

The invention also provides means for indicating which. wave band is selected to go with the desired station. While the invention is applicable to any type of preselector, it is particularly adapted for use with the preselector described and claimed in the copending application oi Mastney and Williams, Ser. No. 633,992, iiled December 10, 1945. In this application, a preselector is disclosed compri-sing an improvement upon the preselector of the Mastney Patent 2,293,299. This preselector is a motor-driven mechanism having a plurality of station selecting means. The preselecting means includes gear trains whereby, at a preselected position. equal and opposite turning forces result. In the application referred to,

2 this motor-driven preselector is provided with a plurality oi push-rods, each of which controls a station to be selected. Each push-rod controls gear drive between a common motor and preselectng unit to be operated. In addition, each push-rod closes the motor circuit whereby lthe mechanism becomes operative.

ln accordance with the invention, the bank of push-rods is adapted to cooperate selectively with one or two switch bars. Each push-rod has a simple means ior determining which of the two switch bars is to be operated. The two switch bars control the selection ci the two wave bands to be operated upon. The push-rods and their mountings may be similar to those shown in Patent 2,213,845. Each push-rod has a head or indicating means cooperating with the simple means to insure that the indication given by the head is consistent with the choice of wave band,

In order that the invention may be more fully described, reference will now be made to the drawing wherein Figure 1 is a perspective view ci a portion of a preselector embodying the present invention. Figure 2 is a diagrammatic view of a tuning system embodying the present invention, certain parts being shown in blocks, and portion of the preselector embodying the present invention being shown in transverse section. Figure 3 is a perspective view showing a push rod, clip and head in exploded form.

Referring particularly to Figure l, Il] indicates the front plate of any type of a preselecting mechanism. In particular, plate I0 in Figure 1 may correspond to plate 5 of the application mentioned above or plate l0 of Patent 2,213,845.

Plate lil is nrovidedwitha series ci slots l2 through which push-rods I3 pass. Push-rods I3 may be oi well-known construction in such a mechanism. As shown here, each consists of a ilat stripof metal having rear portion i4 provided with shouldersy I5 and slots lli and Il. Shoulder I5 limits the outward movement of rod I3, this shoulder engaging plate le. Suitable means, such as a spring. bias each push-rod to an outward position.`

The push-rods may, if desired, have suitable interlocking means whereby any push-rod selected for operation will trip a preceding locked pushrod and will become locked itself in an on posif tion. This on position is that position where the push-rod is in, while the off position is the normal position where the push-rod is out. Such inter- .locking mechanisms are well known, one for example being disclosed in Patent '2,213,845 and in the application referred to above.

Secured to front plate I are end plates 20 and 2|- preferably disposed at or near the ends of iront plate I0. Each end plate has two ears, these being indicated as 22 to 25 inclusive. Pivotally supported at upper ears 22 and 24 is switch actuating plate 25. Pivotally supported at lower ears 23 and 25 is switch actuating plate 2l. As is clearly evident in the drawing, plates 26 and 2l extend toward each other with opposing edge portions being rolled to form outwardly bulging strips 28 and 29. Between the opposed edges of plates 23 and 21 is space 30, this space being wide enough to accommodate the push-rods and the space being long enough to accommodate all push-rods of the preselector mechanism.

Plates and 2l are urged outwardly away from front plate It by any suitable means as by springs SI and 32 disposed between the pivoted plates and front plate l0. Switch plate 26 at one end carries movable contact 33 cooperating with fixed contact 34 on front plate I0. Similarly, movable plate 2l carries movable contact 35 cooperating with fixed contact 36 carried on plate I0. Movable contacts 33 and 35 may be connected to any suitable source of electric power and then to single lead 3l going to terminal 38 oi motor 40. Motor 49 has windings 4| and 42 connected loe-- tween common terminal 38 and xed contacts 36 and 34 respectively. Motor 40 may be any suitable electromagnetic device as a push-pull solenoid for moving arm 43, this arm being mechanically connected to any kind of band switching mechanism shown in block form and indicated as 44. Such switching mechanism may consist of one or more banks of switches such as, Y*

for example, shown in Patent 2,185,949. Any other wave changing system switch may be used, it being` understood that arm 43 may be either pivotally or longitudinally moved for effecting switch operation. selection may be obtained by selectively energizing coils 4I or 42 of motor 40.

Each push-rod I3 is mechanically or electrically connected to any suitable preselecting mechanism 45. Thus, the connection between the push-rods and preselecting mechanism may be both mechanical and electrical, such as for example shown in the application previously referred to. A mechanical connection between the push-rod and preselecting means may be as disclosed in Patent 2,316,270. Another preselecting mechanism to which the push-buttons and pushrods may be applied is shown in Patent 2,305,123. Preselecting mechanism 45 may operate upon tunable elements 4G of the radio receiver, in its simplest form this consisting of one or more gang condensers.

In order to control the wave band, each pushrod I3 is provided with spring clip 50. Spring clip 59 has parallel slotted portions 5I and 52 which may be threaded over rod I3. Slotted portion 52 is threaded over reduced end 53 of a pushrod. Reduced end 53 is provided with opposed notches 54 at the junction between portions 53 and the main body portion of rod I3. Spring clip is sprung into position as shown with retaining portion 52 locking in one of notches 54.

It will be evident that band Notches 54 may be omitted or only one may be provided.

Slotted portion 52 has index portion 55 bent over as shown toward the iront of rod I3.

It will be evident that spring clip 50 may be disposed over rod I3 in one of two positions, namely with the major portion of the clip above or below rod i3. As shown in Figure 3, spring clip 5U has moet of its body disposed below rod I3. Thus, spring clip 50 has operating face 56 below rod Figure 1 shows a number oi push rods, each rod having its individual spring clip, certain clips being in one position and other clips being in another position.

Push-button head of any suitable material such as plastic is provided with slot 5I into which reduced end 53 of a push-rod its. Head 30 also has index slot 82 for cooperation with index portion Each spring clip 50 is just long enough so that, when a push-rod is forced in, face 56 of the spring Clip will engage one of switch actuating plates 25 and 2l'. Thus, a selection of wave be d for reception will be made simultaneously n the selection of station.

1t is clear that head E0 can be oriented only in correct position with relation to the position of spring clip 50.

What is claimed is:

l. A push-button tuner for radio receivers including a series of transversely aligned, longitudinally movable operating rods, each rod controlling a station setting, two switch bars on opposite sides of the series of rods, every rod being equidistant from the two switch bars, a spring clip for each rod and attachable thereto in one oi two positions only, said two positions being degrees apart, each clip having an engaging portion extending away from its rod in one direction only so that the projection of said portion falls on a switch bar, said rod normally having a position where the engaging portion of its spring clip is free, said rod during actuation bringing the clip portion into engagement with a switch bar, each switch bar controlling a circuit for an electrical wave band selector.

2. rEhe structure of claim 1 wherein each clip has an index portion and each rod has a removable head bearing wave band identiiication, the head being mountable on a rod in either of two positions corresponding to the two clip positions, a head and clip having intertting parts whereby a head can be positioned on its rod only in the correct position corresponding to the clip position.

JOHN H. WILLIAMS.

REFERENCES CITED The following references are of record in the ille ci this patent:

UNITED STATES PATENTS Number Name Date 2,251,058 Rinia July 29, 1941 2,356,935 Koch Aug. 29, 1944 FOREIGN PATENTS Number Country Date 511,503 Great Britain Aug. 21, 1939 

